• Journal of Microbiology and Biotechnology
• /
• v.21 no.11
• /
• pp.1184-1192
• /
• 2011

A bacterial isolate (strain JS-2) characterized as Bacillus sp. was challenged with high concentrations of toxic selenite ions. The microbe was found to transform the toxic, soluble, colorless selenite (${SeO_3}^{2-}$) oxyions to nontoxic, insoluble, red elemental selenium ($Se^0$). This process of biotransformation was accompanied by cytoplasmic and surface accumulation of electron dense selenium ($Se^0$) granules, as revealed in electron micrographs. The cells grown in the presence of selenite oxyions secreted large quantities of extracellular polymeric substances (EPS). There were quantitative and qualitative differences in the cell wall fatty acids of the culture grown in the presence of selenite ions. The relative percentage of total saturated fatty acid and cyclic fatty acid increased significantly, whereas the amount of total unsaturated fatty acids decreased when the cells were exposed to selenite stress. All these physiological adaptive responses evidently indicate a potentially important role of cell wall fatty acids and extracellular polymeric substances in determining bacterial adaptation towards selenite-induced toxicity, which thereby explains the remarkable competitiveness and ability of this microbe to survive the environmental stress.

• Proceedings of the Korean Society of Crop Science Conference
• /
• 2023.04a
• /
• pp.71-71
• /
• 2023

• KOREAN JOURNAL OF CROP SCIENCE
• /
• v.69 no.1
• /
• pp.1-14
• /
• 2024

High soil salinity is the most severe threat to global rice production as it causes a significant decline in rice yield. Here, we investigated the effects of various plant extracts on rice plant stress associated with high salinity. Additionally, we examined various physiological and biochemical parameters such as growth, photosynthetic activity, chlorophyll content, and lipid peroxidation - in rice plants after treatment with selected plant extracts under salt stress conditions. Of the 11 extracts tested, four - soybean leaf, soybean stem, moringa (Moringa oleifera), and Undaria pinnatifida extracts - were found to effectively reduce salt stress. A reduction of only 3-23% in shoot fresh weight was observed in rice plants under salt stress that were treated with these extracts, compared to the 43% reduction observed in plants that were exposed to stress but not given plant extract treatments (control plants). The effectiveness varied with the concentration of the plant extracts. Water content was higher in rice plants treated with the extracts than in the control plants after 6 d of salt stress, but not after 4 d of salt stress. Although photosynthetic efficiency (Fv/Fm), electron transport rate (ETR), and the content of pigments (chlorophyll and carotenoid) varied based on the types and levels of stress and the extracts that the rice plants were treated with, generally, photosynthetic efficiency and pigment content were higher in the treated rice compared to control plants. Reactive oxygen species (ROS), such as superoxide radicals, hydrogen peroxide (H₂O₂), and malondialdehyde (MDA), increased as the duration of stress increased. ROS and MDA levels were lower in the treated rice than in the control plants. Proline and soluble sugar accumulation also increased with the duration of the stress period. However, proline and soluble sugar accumulation were lower in the treated rice than in the control plants. Generally, the values of all the parameters investigated in this study were similar, regardless of the plant extract used to treat the rice plants. Thus, the extracts found to be effective can be used to alleviate the adverse effects of stress on rice crops associated with high-salinity soils.

• Journal of Biosystems Engineering
• /
• v.38 no.2
• /
• pp.163-170
• /
• 2013

Purpose: The purpose of this study is to provide analysis of physiological, biomechanical responses occurring from the operation to lifting or twist lifting task appears frequently in agricultural work. Methods: This study investigated the changes of physiological factors such as heart rate, heart rate variability (HRV) and biomechanical factors such as physical activity and kinetic analysis in the task of twisting at the waist while lifting. Results: Heart rates changed significantly with the workload. The result indicated that the workload of 2 kg was light intensity work, and the workload of 12 kg was hard intensity work. Physical activity increased as the workload increased both on wrist and waist. Besides, stress index of the worker increased with the workload. Dynamic load to herniated discs was analyzed using inertial sensor, and the angular acceleration and torque increased with the workload. The proposed measurement system can measure the recipient's physiological and physical signals in real-time and analyzed 3-dimensionally according to the variety of work load. Conclusions: The system we propose will be a new method to measure agricultural workers' multi-dimensional signals and analyze various farming tasks.

• Proceedings of the Korean Society for Emotion and Sensibility Conference
• /
• 1998.04a
• /
• pp.44-56
• /
• 1998

Effects of the music and white noise on recovery of the autonomic and cortical responses evoked by aversive visual stimulation were analyzed in 20 subjects. It was suggested that the music is able to exert modulatory influence on the physiological activity resulted from exposure to unpleasant IAPS based stimuli. Spectral power of DDG, heart rate(HR)respiration rate (RSR) and electrodermal activity(EDA)were recorded and analyzed for each experimental condition. It was observed HR and RSR deceleration, increased EDA and electrocortical activation expressed in decreased alpha power and increase of delta activity ao occipital and frontal areas. Obtained results suggest that audutory stimulation both with pleasant and sad music lead to restoration of pre-stimulation activation levels of most physiological parameters during listenning to music and in post-stimulation period. White noise evoked short-term physiological responses typical for orienting reaction and quite distinct from changes produced by music. Available data to differentiate effeces among pleasant and sad music, due toqualitative similarities of physilolgical patterns, but suppert an assumption that music is capable to facilitate the process of recovery of physilolgical responses elicited by visual stimulation of negative valence, thus positively modulate post-stress state.

• Proceedings of the Safety Management and Science Conference
• /
• 2008.04a
• /
• pp.221-230
• /
• 2008

This paper reviewed the relationship between job characteristics and job stress responses(physiological response, psychological response, behavioral response), and the moderating effect of social support. Based on the responses from 187 employees in small & medium manufacturing industry, hierarchical regressional analysis showed that job characteristics factors have partly negative relationships with job stress response. But, job variety has positive relationship. Social support has partly moderating effect on the relationship between job characteristics and job stress.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.770-776
• /
• 2000

This paper represents our efforts to diagnose nutrient stresses using physiological instruments in cucumber plants. The stresses could be detected by measuring and analyzing the difference of chlorophyll content, photosynthetic efficiency(Fv/Fm), differential temperature(DT), stomatal resistance and light absorbance values between deficient and controlled plants. From the all over experiments, the stresses could be first diagnosed in the 8th day after treatment and the overall diagnosis rate was estimated at more than 50%.

• Proceedings of the Korean Society for Agricultural Machinery Conference
• /
• 2000.11c
• /
• pp.736-743
• /
• 2000

This paper represents our efforts to diagnose environmental stresses using physiological instruments in cucumber plants. The stresses could be detected by measuring and analyzing the difference of chlorophyll content, photosynthetic efficiency(Fv/Fm), differential temperature(DT), stomatal resistance and light absorbance values between treated and controlled plants. From the all over experiments, the stresses could be first diagnosed on the 1st to 5th day after treatment and the overall diagnosis rate was estimated at more than 50%.

• The Korean Journal of Emergency Medical Services
• /
• v.8 no.1
• /
• pp.47-55
• /
• 2004

The purpose of this study were to investigate the effect of meditative respiration training for 6weeks on the changes of ACTH and Cortisol which are stress hormones in 10 male workers. The results of this study were as follows : 1. After meditative respiration training for 6weeks, the changes of heart rate, respiratory rate, SBP, DBP were slightly decreased. 2. After meditative respiration training for 6weeks, the changes of ACTH hormone were significantly decreased(p<.01). 3. After meditative respiration training for 6weeks, the changes of cortisol hormone were significantly decreased(p<.05). The above conclusions suggested that short-term meditative respiration training was an effective training method to changes mental emotional states and physiological stress hormone level affirmatively. Further, the future researches must analyze the physiological and psychological characteristics affecting mental health synthetically and develop meditative respiration program suitable to the various items and classes, especially EMT.

• Agricultural and Biosystems Engineering
• /
• v.2 no.1
• /
• pp.1-6
• /
• 2001

This paper represents methods to diagnose nutrient deficient stresses of cucumber plants using several physiological instruments. The stresses could be detected by measuring and analyzing the difference of chlorophyll content, photochemical efficiency (Fv/Fm), temperature difference (DT) and light absorbance at wavelengths of 480nm, 560nm and 710nm between deficient and control plants. From the all over experiments, the stresses could be first diagnosed in the 3rd to 5th day in general after treatment and the overall diagnosis rate was estimated at more than 50% up to 100%.